It appears that certain radial engined aircraft get no cooling advantage but do indeed get a drag penalty for having radiators open.This affects Hellcats, Jugs and I'm thinking Corsairs, Wildcats...maybe a few bomber/twin attack aircraft. More testing will be required...but no sense in wasting airspeed to get your radiators open unless someone finds otherwise.

Testing reveals time to overheat and engine failure to be identical with radiator open and with it closed.F4UA also has this problem.13:40 to breakdown, radiator open or closed. Again, a 20km/h speed loss for open radiator (570-550), for no benefit.It seems like 1C just used the same heating values for all these planes so far. FW, F6F and F4U all have engine breakdown in about 13½ minutes with rad open.

Except, FW190 will break down in 8:20 with radiator closed. The bug benefits the affected planes (they get free cooling, and 13:30 breakdown time, even with flaps closed).

La5FN gains no cooling from radiator flaps, but loses 25km/h from them. It also overheats and breaks down quickest of all the planes tested.This one's weird, because I could swear I tried La5FN before in FB, and the radiator did extend the breakdown time. No idea why it's stopped working.

Results so far (plane/breakdown time @ 1000m/TAS)-------------------

F6F3 (closed) / 13:30 / 520F6F3 (open) / 13:30 / 500

F4UA (closed) / 13:45 / 570F4UA (open)/ 13:45 / 550

P47D27 (closed) / 13:40 / 585P47D27 (open) / 13:40 / 560

FW190A5 (closed) / 8:20 / 585FW190A5 (open) / 13:30 / 560

LA5FN (closed) / 7:40 / 600LA5FN (open) / 7:40 / 575

109K4 (closed) / 9:15 / 605109K4 (open) / 11:20 / 585

SpitVb (closed) / 8:18 / 470SpitVb (open) / never / 455

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So far only radial engine plane that works properly is FW-190. I am glad I know this now, I won't waste speed on the rad flaps online!

Results as you'd expect. Better than La-5, worse than P-47 and company. Note: Radiator drag is very much reduced from 3.04. Used to drop speed by 50km/h, now only 20km/h. 2 extra minutes of WEP, for only 3% drop in speed; a bargain!

F4UA with 120% fuel test had to be done at 500m, because at 1000m, it's over-rich (and get those brown trails).Time to overheat is the same. 3:30 for message, 13:40 for engine damage. Speed is the same, 570km/h.Didn't seem to make any difference at all.Top sustainable speed on deck, 120% and 100% fuel, is 577km/h.

It is important to understand that the sign of the early Finnish Air Force has nothing to do with the Nazi Germany.The blue swastika was the symbol of good fortune used by the Swedish Count Eric von Rosen!"